Fuse construction



Feb. 9, 1943. w o SCHULTZ ET AL 2,310,466

FUSE CONSTRUCTION Filed July 28, 1939 4 Sheets-Sheet 1 IN VEN TORJ Mum/14 (Q Sew 0.422 BY Az-u/m/ d Jaw 444m? ATTO NEY Feb. 9, 1943. w. o SCHULTZ E'I'AL 2,310,456

FUSE CONSTRUCTION Filed July 28, 1939 4 Sheets-Sheet 2 INVEN TORS M11 M44 (2 Jam/z rz BY rlLlV/N G draw/144m? ATTORN Y 1943- w. o. SCHULTZ ETAL 0, 66

FUSE CONSTRUCTION Filed July 28, 1959 4 Sheets-Sheet 3 IN V EN T0115 Wax/4M 0.50/1/1/1 BY AM/A/ 6." jffiM M/ffi w. o. SCHULTZ ETAL .46

FUSE CONSTRUCTION Filed July 28, 1939 4 Sheets-Sheet 4 INVENTORS M104 (9 \Samrz fizz/w 5 J/f/M MYAW ATTORN Patented Feb. 9, 1943 2,310,466 FUSE CONSTRUCTION William 0. Schultz, South Milwaukee, and Alwin G. Sei

t nmayer, Milwaukee, Wis., assignors to Line Material Company, South Milwaukee, Wis., a corporation of Delaware Application July 28, 1939, Serial No. 286.980

25 Claims.

This invention relates to fuse constructions.

The primary oblect of this invention is to incorporate in a fuse device means for manually opening the circuit under load and to so form the device that no damage is done the apparatus although the circuit may be opened under heavy overload.

It frequently happens that where cut-outs areemployed to protect important feeders, that it becomes desirable at times to sectionallze these feeders with a conventional switch stick. -When the load on the feeders is of considerable magnitude, it frequently happensthat a long are is drawn when an ordinary switch is opened, and in addition to'this under these conditions flashover between adjacent parts frequently occurs.

This invention is designed to provide a novel form of fuse construction in which the automatic functioning of the fuse under overload is preserved and at the same time means are provided whereby the circuit may be manually opened under load and to so construct the device that the arc is confined within the fuse tube whether the fuse is severed automatically or manually and so that the expulslve action in either case is employed to quickly extinguish the arc and permit' interrupting of the circuit with perfect safety.

Further objects are to, provide an inexpensive construction which though it is capable of being manually operated to open the circuit under load, nevertheless is simple and employs very few 'easily produced parts.

Figure 2 is a fragmentary view of the construction shown in Figure 1 with parts: broken away 4 and parts in section.

Figure 3 is a sectional Figure 2. v

Figure 4 is a sectional view on the line H of Figure 3.

Figure 5 is a fragmentary view.with parts broken away showing a further form of the invention.

Figure 6 is a bottom view of the structure shown in Figure 5.

Figure 7 is a. fragmentary view with parts broken away of another form of the invention.

Figure 8 is a bottom view of the structure shown in Figure 7.

Figure 9 is a rear view of the lower portion of the structure shown in Figure 7 of the fuse. tube as it appears removed from the support, the thumb nut being removed.

Figure 10 is a view of a different type of link that may be used with any form of the invenview on the line 3-4 of tion.

The form of the invention shown in Figures 1 to 4 will first be described.

The device may be mounted upon opposite ends of an insulator I, the center part of which is supported by means of the clamp or other suitable member 2 from any desired support, or if desired, the upper and lower stationary contacts can be carried by separate insulators. The upper contact comprises a housing 3 which is provided with a suitable connector 4 by means of which a line wire may be attached, and this housing is equipped with a spring pressed latch 5 which normally fits over the tip or pin 6 of the removdownwardly extending arm In which is plvotally mounted on a-lever H. The arm Ill is provided with a portion 12 which is securely attached to the fuse tube adjacent its lower end.

The lever II is provided with trunnions ii on opposite sides thereof which fit within hook shaped brackets or supports it of the lower contact IS. The lever II is also provided with a rearwardly extending contact portion l6 which is'engaged, under normal conditions, by the contact spring I l as shown in Figure 1.

The lower stationary contact I5 is provided with a connector It. The upper and lower con- 'tacts are secured to the'upper and lower ends of the insulator l in any suitable manner as by means of the clamping brackets illustrated. The lever ll extends outwardly and is provided with an upwardly curved arm IQ for a purpose hereinafter to appear. It is also provided on one side thereof with a threaded shank 20 upon which a thumb nut 2| is screwed to attach the leader 22 of a fuse link.

The fuse link includes a reduced fusible section 23. If desired, the fuse link may be constructed as shown in Figure 2 or as shown in Figure 10. As shown in Figure 2, the upper end of the fuse link is provided with a shank portion 24 terminating in a spherical member or ball 25 which is gripped by the spring fingers 26 formed in a tubular member. The upper end of the tubular member is outwardly flared and fits within a washer 21 so that the upper portion of this composite fuse link may be clamped by the cap I of the fuse tube.

As shown in' Figure 4, a convenient way of constructing the lever II is to provide the lever with the bifurcated rear portions'within which the hub 28 of the downwardly projecting arm Hi ls located.

The upper end of the fuse tube may be provided with an eyelet 29, see Figure l, which is ually rock the fuse -tube outwardly. Preferably II which is spring pressedby means of the spring I! towards rotation in a clockwise direction as viewed in Figure 1. Also the weight of the fuse tube and its associated parts, as well as the downward pressure-of the spring 32, biases the lever ll towards rockingmotion to extract any remaining portion of the fuse link. During this motion, the pivot pin 33 which Joins the arms ID" to the lever l I, moves outwardly and downwardly and thus rocks the lower end of the fuse tube outwardly and downwardly, thereby moving the upper end of the fuse tube out ofengagement with the latch and allowing the fuse to drop to open position away from the upper contact.

In refusing, the fuse tube may be'readily detached from the book supports I4 by means of a switch stick inserted in the eyelet portion In of the arm l0. Thereafter a new fuse is placed in service and the device is repositioned within the supports I4 and thereafter rocked into operative position by'means of the switch stick It sometimes becomes desirable'to sectionalize a line and this necessity may occur while the line Thiis it will be seen thatthe circuit may be readily opened even under load without any danger whatsoever to the apparatus and without danger to thefoperator, as *the operator stands away from the bottom of the fuse tube at the time he jerks downwardly on the switch stick.

The invention may take other forms. For ex.- ample, as shown in Figure 5, thelower portion of the fuse tube 39 is illustrated as provided with a. member 46 securely attached adJacent the.

lower end of the fuse tube and preferably equipped with a projecting tongue 4| to facilitate handling-by a suitable switch stick. The member 40 pivotally carries a lever 42 which is pivoted as indicated at 43 to such member and which extends downwardly and is provided with laterally pro- -jecting trunnions 44 which maybe in the form of a pin, if desired, andwhich .are removably received within the hook-shaped supports 45 of the lower terminal or contact 48. A. brush contact 49 may be carried bythe stationary contact 48 and may bear against the lever 42 as shown in Figure 5. The lever 42 -is provided with a threaded shank '50 and with a thumb nut 5| for clamping the flexible leader 62 of the fuse link in place;

The stationary upper contact may be as here- Iinbefbre described and the upper portion of the fuse tube may also be as hereinbefore described. The upper and lower contacts may be carried asillustrated in Figure 1,. or may be carried by separateinsulators one of which is indicated at as in Figure 5, and it is obviou's .that any form iscarrying a load. The circuit'may be readily.

interrupted by hooking thehook 34 of a switch stick, see Figure 1, over the upwardly curved portion IQ of the arm II and thereafter quickly 7 I notched out and normally bears against the drawing downwardly, thus rupturingthecircuit wlthin'the fuse tube. 1

If the type of link shown in Figure 2 is employed, the destruction of the" link .does not necessarily take place as theball 25 is withdrawn from the grip of the spring fingers 26, thev grip of the spring fingers on the ball being less than the strength of the weakest portion 23 of the fuse link. Thus the circuit is broken withinthe fuse tube, and in addition to the mechanical Buick downward withdrawing of the fuse link, the expulsion action also occurs to assist in clearing the fuse tube. The fuse link as shown in Figure 2 may be again used provided the load has not been too heavy and destruction of the link-has not occurred during this manual opening-of the v circuit.

On the other hand, if it is desired, an ordinary type of fuse link such as shown in Figure 10 inay be employed, in which the fuse link is provided with the usual button-head 35, the shank 36, the 1 reduced fusible section 31, andthe flexible leader 38 corresponding to the flexible leader 22. Under these conditions, when the circuit is manually opened by a quick downward jerk imposed on the lever i I, the fuse link is ruptured at'its weakest portion 31 and the circuit is therefore interrupted within the fuse tube and any remaintured by an electrical overload.

ofthe device may be carried by any suitable type of-insulator, two different mountings being shown for illustration.

Thelever- 42has an extension 42 which is lower side portion of the fuse tube 89, as shown in Figures 5 and 6. A second lever 54 is pivotally mounted on the trunnions 44 of the lever 42.

The lever 64 extends laterally across the bottom and of the fuse tube and is provided with an enlarged opening 55 so that thereis no ob- 'struction to the free flow of gases through the bottom open end of the fuse tube 39, as is apparent from Figure 6. L

J The leader 52 'of the fuse link passes through this opening and is looped over. the rounded rear portionof the lever 42. The lever 64 extends forwardly and is provided with an upturned portion 66 within which the hook of a switch stick may-be positioned so as to permit manual opening of the circuit under load as hereinbefore described. Any suitable type of fuse link can be employed with this form of the invention as described, for example, in connection with the first form of the invention.

In the form of the invention-shown in Figures 7, 8 and 9 the fuse tube 51 is provided with a .member 58 adjacent, its lower portion which is thereto as indicated at so and which extends is indicated at 64 and may be provided with a downwardly and is normally positioned against the rear side of the fuse tube as shown in Figure 7. This-lever is provided with a threaded shank 6| which carries a thumb nut 62 for securing the flexible leader 63 of the fuse link as hereinbefore described. The lower stationary'contact brush contact 6! bearing against the lever 69 and urging the fuse tube ,towards outward rock-' ing motion as shown in Figure 5..

Howeven -a separate member 66 is providedwhich is independent of the lever. Thisme ber 66 may be substantially- U-shaped as shown in Figure 8, and is pivotally mounted as indicated at 61 upon the member 58 carried by the fuse tu The member 65 is provided with an eyelet portion 68 which is adapted to be engaged by a switch stick when it is desired to manually open the circuit within the fuse tube as hereinafter described. It is also provided with a cam portion 69 which engages the rollers or pins carried by the lever 59.

The lever 59 is provided with outwardly pro- Jecting trunnions H which'are remcvably seated within the hook portions I2 of the lower stationary contact 64.

If desired, the lower end of the lever 59 may be slightly notched out as indicated at I3 to assist in positioning the flexible leader 6! as shown most clearly in Figure 9.

-The operation of this form of the invention.

is substantially the same as hereinbefore described. When an overload occurs, the fuse link is ruptured, the lever 59 released, and the lower end of the fuse tube moves outwardly and downwardly, thus detaching the upper end of the fuse tube from the latch and allowing the fuse tube to swing downwardly and outwardly. When the apparatus is manually operated to open the circuit within the fuse tube, the operator inserts the switch stick within the eyelet 68, see Figure 7, and Jerks downwardly thereon causing the cam portion 69 to press against the rollers or pins 10 and thus rock the lever 59 to the left as viewed in Figure '7, thus withdrawing the fuse link and opening the circuit within the fuse tube.

Any suitable formof fuse link can be employed with this form of the invention as hereinbefore described.

The stationary contacts of this form of the invention may be mounted on separate insulators, one of which is shown in Figure 7 at M, or they may be carried at the upper and lower ends of a single insulator as shown in Figure 1. In fact, any suitable interchange of parts from one form of the invention to the other may be employedwithoutdeparting from the spirit of this invention.

It is to be noted that a considerable lever arm or leverage is afforded by the manual operation 'of the apparatus shown in each ofthe inventions. For example in Figures 1 and 5 the multiplication of forces is obtained as the portions l9 and 56 are respectively positioned at a considerably greater distance from the pivot point than the portions of the levers which engage the fuse link. In the form of the invention shown in Figure 7 a cam action is secured in addition to the increased leverage afforded by the engagement of the switch stick within the eyelet 68 which is at a point relatively greater from the pivot point 61 than the point of engagement between the cam portion 69 and the rollers 10.

It is to be noted that in all forms of the invention and with whatever type of fuse link employed, the invention comprehends the interruption of the fuse link by overload on the one hand, or the interruption of the fuse link by manually operable means on the other hand.

In other words, where the composite fuse link of the form shown in Figure 2 is employed, the fuse link is severed or interrupted by manual operation as the Darts of the fuse'link are pulled apart and the fuse link also is severed by elec- I 3 trical overload due to the fusing of the fusible section, and in the form shown in Figure 10, for

instance, the fuse link is severed or ruptured by electrical overload due to fusing of the fusible section and is also severed or ruptured by the manually operable means by pulling the fusible section apart. Thus it' is clear that inall-forms ofthe invention the fuse link may be severed or ruptured either by electrical overload or by the manually operable means.

It will be seen that circuit interrupters have been provided by this invention which are so made that they will release on overload conditions and will also release when tension above a predetermined value is imparted to the conducting means to either rupture the fuse link at its weakest point, namely, the fusible section, or to separate the ball from the spring fingers 26, as shown in Figure 2.

In all forms of the invention it is to be noted that the mechanism for holding the fuse tube in its latched or terminal bridging condition is dependent on the continuity of the conducting means extending through the fuse tube. When this conducting means is severed or ruptured by the fusing of the fuse link or by the breaking of the fuse link' by excessive pull thereon, or by separating the ball 25 from the spring fingers 28 of Figure 2, the mechanism holding the fuse tube in terminal bridging position is released and the fuse tube executes its drop-out motion.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

We claim:

1. A fuse device comprising a fuse tube having an open end, a fuse link within said fuse tube adapted to rupture upon overload, stationary contacts normally connected to form a circuit through said fuse link, and manually operable means located adjacent the open end of said fuse tube for breaking the fuse link thereby breaking the circuit within'said fuse tube by the force manually imparted to said means.

2. A fuse device comprising an expulsion fuse tube hearing an open end, a pair of stationary contacts, a--fuse link within said fuse tube normally electrically connecting said stationary contacts and adapted to rupture within said fuse tube upon overload, and means for breaking the connection between said stationary contacts within said fuse tube independently of load conditions by directly pulling said fuse link from said fuse tube independently of the normal action of said means.

*3. A fuse devicecomprising an expulsion fuse tube having an open end, a pair of stationary contacts, a fuse link within said fuse tube normally electrically connecting said stationary contacts and adapted to rupture within said fuse tube upon overload, and externally operable means for breaking the connection between said stationary contacts within said fuse tube independently of load conditions by imparting an excess pull on said fuse link in a directiontowards the open end of said fuse tube.

tacts and adapted to rupture within said fuse .tube upon overload, and manually operable means for breaking theconnection between said position, and g g mitting a direct pull to said fuse link from said stationary contacts 'within' said fuse tube independently of load conditions by imparting an excess pull on said fuse link towards the open end of said fuse tube.

\ 10. A drop-out fuse device comprising an upper and a lower stationary contact. iuse tube ineluding a fuse link normally electrically connect- 5. .A fuse device comprising an expulsion fuse to receive a switch stick for breaking the connec-- Q tion between said stationary contacts within said fuse tube independently of loadconditions by transmitting the force from said switch stick to said fuse link to withdraw said fuse link.

6. A fuse device comprising an expulsion fuse tube having an open end, a pair of stationary contacts, a fuse link within said fuse tube normalLy' electrically connecting said stationary contacts and adapted to rupture within said tube upon overload, and means having a portion operable externally of said fuse tube and adapted to receive a switch stick for breaking the connection between said stationary contacts within said fuse tube independently of load conditions by transmitting the force from said switch stick to said fuse link to withdraw said fuse link, said means'leaving the open end ofsaid fuse tube ing said contacts and normally occupying an operative position and movable to inoperative position away from said upper contact, a lever pivotally supported from said lower contact and controlled by said fuse link for normally holding I said fuse tube in operativeposition and releasable upon the occurrence of an overload, said lever placing;a tension on said fuse link, and

means adapted to be engaged by a switchsstick for causing said lever to interrupt the connection between the upper and lower stationary contacts within said fuse tube independently of load conditions by increasing the tension on said fuse link.

l1. 'A drop-out fuse construction comprising upper and lower stationary contacts, a fuse tube normally occupying an operative position and inovable to inoperative position and including. a fuse link normally electrically connecting said upp r unobstructed, whereby expulsive action will ocour when interruption .occurs either by-fusing of the fuse link 'or by operation of said means,

said fuse link at the projecting portion of said" fuse link for interrupting the circuit within said fuse tube independently of load conditions by transmitting said force to said fuse link to withdraw said fuse link from said fuse tube.

8. A drop-out fuse device comprising a pair of. stationary contacts, a fuse tube having an open end and having a fuse link normally electrically connecting said stationary contacts and projectand lower contacts, a lever controlled by said fuse link for normally holding said fuse tube in operative position and releasable upon rupture;

of said fuse link, and manually operable means for causing said lever to rupture. said fuse link by transmitting force applied to said manually operable means to said. fuse link. I

12. A drop-out fuse construction comprising upper and lower stationary contacts, a fuse tube normally occupying an operative position and movable to inoperative position and including a fuse link normally electrically connecting said upper and lower contacts, a lever controlled by' said fuse-link for normally holding said fuse tube in operative position and releasable'upon rupture of said fuse link. and manually operable means,

.. in operative position and releasable upon rupture ing from the open end of said fuse tube, said fuse 5 tube being movable from operative to inoperative position, mechanism controlled by said fuse link for normally holding said fuse tube in operative manually operable means for transmanually operable means for interrupting the connection between said stationary contacts within said fuse tube, said mechanism whensaid manually operable means has operated releasin said fuse tube for drop-out motion. a

9. A, drop-out fuse device comprising a' pair of stationary contacts, a fuse tube having an open end, a fuse link within said fuse tube and projecting from the open end of said fuse tube, said fuse tube normally occupying an operative position between said stationary contacts within said fuse tube and for releasing said nechanism from the control of said fuse link.

of said fuse link. and a secondmanually operable lever for rupturing said fuse link independently of any motion of said first lever.

14. A drop-out fuse construction comprising an upper and a lower stationary contact, an expulsion-fuse tube having a lower open end andincludin a fuse link-normally electrically connecting "sa d stationary'contacts/said fuse tube nor- .mally occupying an operative position and being movable outwardly away from said upper contact,

. and a lever pivotedto said lower contact and pivotally connected to said fuse tube for holding said fuse tube in operative position, said lever being controlled by said fuse link, said lever having a manually operable portion whereby said lever may be manually operable to rupture said fuse link and release said fuse tube.

15. A drop-out fuse device comprising upper and lower stationary contacts, an expulsion fuse tube having an open lower end and including a fuse link normally electrically connecting said stationary contacts, said fuse tube normally occupying an operative position and adapted to drop outwardly away from said upper contact to an inoperative position, a lever pivoted to said lower contact and pivoted to said fuse tube and normaliy restrained by said fuse link, and a secondmanually operable lever for rocking the first mentioned lever to rupture said fuse link within said fuse tube.

16. A drop-out fuse device comprising an upper and a lower stationary contact, an expulsion fuse tube having an open lower end and including a fuse link normally electrically connecting said stationary contacts, said fuse tube normally occupying an operative position and movable to inoperative position away from said upper contact, a first lever pivoted upon said lower contact and pivotally supporting said fuse tube and normally holding said fuse tube in operative position, said lever being restrained by said fuse link, and a second lever movable independently of said first lever and engaging said fuse link, said second lever having a manually operable portion whereby said second lever may be operated to rupture said fuse link and release said first lever.

17. A drop-out fuse construction comprising upper and lower stationary contacts, a fuse tube normally occupying an operative position and movable to inoperative position and including a fuse link normally electrically connecting said upper and lower contacts, said fuse link having a fusible section, a lever controlled by said fuse link for normally holding said fuse tube in operative position and releasable upon rupture of said fuse link, and manually operable means located adjacent the lower contact for rupturing said fuse link at said fusible section, said means being accessible exteriorly of said fuse tube and transmitting a pull to said fuse link from force applied to said means.

18. A fuse device comprising a fuse tube, a pair of stationary contacts, a fuse link frictionally held in operative position and normally electrically connecting said contacts, said fuse link having a fusible section, and means for imparting an excess pull on said fuse link for interrupting the frictional hold on said fuse link to break the connection between said contacts, the mechanical strength of the fusible section being greater than the frictional hold on the fuse link.

19. A fuse device comprising stationary contacts, a fuse link normally electrically connecting said contacts, said fuse link having a fusible section, separable means normally holding said fuse link in operative position, and means for imparting an excess pull on said fuse link for separating said separable means without rupturing said fusible section, the mechanical sti'ength of the fusible section being greater than the holding power of said separable means.

20. A drop-out fuse construction comprising upper and lower stationary contacts, a fuse tube normally occupying an operative position and movable to inoperative position and including a fuse link normally electrically connecting said upper and lower contacts, said fuse link having a. fusible section, a lever controlled by said-fuse link for normally holding said fuse tube in operative position and releasable upon rupture of said fuse link, separable means normally holding said fuse link in operative position, and manually operable means for causing said separable means to separate without rupturing said fusible section by transmitting the force applied to said manually operable means to said fuse link.

21. A drop-out fuse construction comprising upper and lower stationary contacts, a fuse tube normally occupying an operative position and movable to inoperative position and including a fuse link normally electrically connecting said upper and lower contacts, said fuse link having a fusible section, a lever controlled by said fuse link for normally holding said fuse tube in operative position and releasable upon rupture of said fuse link, separable means located within and adjacent the upper end of said fuse tube normally holding said fuse link in operativ position, and manually operable means for causing said separable means to separate without rupturing said fusible section by transmitting the force applied to said manually operable means to said fuse link.

22. A fuse construction comprising stationary contacts, a fuse tube including a fuse link normally electrically connecting said stationary contacts, said fuse link having a flexible conductor portion and a fusible section adapted to melt on. electrical overload, separable friction means located within said fuse tube and adjacent one end of said fuse link for normally mechanically holding said fuse link in operative position, and means operable externally of said fuse tube for imparting an excess pull on said fuse link for separating said separable friction means Without rupturing said fusible section.

23. A circuit interrupter comprising a pair of spaced terminals, an expulsion tube normally bridging said terminals and supported for dropout motion, a conductor extending through said tube and normally electrically connecting said terminals, said conductor including a yieldingly maintained severable joint, mechanism controlled by said conductor and dependent upon the integrity of said conductor for maintaining said tube in its normal bridging relation to said terminals, said interrupter including means responsive to an electrical overload for interrupting the continuity of said conductor and including means for interrupting said severable joint.

24. A circuit interrupter comprising a pair of spaced terminals, an expulsion tube normally bridging said terminals and supported for dropout motion, severable conducting means within said tube, said conducting means including a yieldingly maintained joint severable when tension above a predetermined value is directly imparted to said conducting means, and mechanism for imparting tension above said predetermined value to said severable conducting means, said mechanism normally maintaining said tube in terminal bridging relation and being dependent upon the continuity of said severable conducting means and releasing said tube for drop-out motion when the continuity of said severable conducting means is interrupted.

25. A circuit interrupter comprising a pair of spaced terminals, an expulsion tube normally bridging said terminals and supported for dropout motion, a conductor extending through said tube and normally electrically connecting said terminals, said conductor including a yieldingly maintained severable loint, mechanism controlled by said conductor and dependent upon the integrity of said conductor for maintaining said tube in itsnormal bridging relation to said terminals, said interrupter including means for severing said Joint and thereby interrupting the continuity of said conductor.

WILLIAM O. SCHULTZ. ALWIN G. ST'EINMAYER. 

